How to Feed Data-hungry Mobile Devices? Use More Antennas

Researchers from Rice University today unveiled a new multi antenna technology that could help wireless providers keep pace with the voracious demands of data hungry smartphones and tablets. The technology aims to dramatically increase network capacity by allowing cell towers to simultaneously beam signals to more than a dozen customers on the same frequency.

Details about the new technology, dubbed Argos, were presented today at the
Association for Computing Machinery's MobiCom 2012 wireless research conference
in Istanbul. Argos is under development by researchers from Rice, Bell Labs and
Yale University. A prototype built at Rice this year uses 64 antennas to allow a
single wireless base station to communicate directly to 15 users simultaneously
with narrowly focused directional beams.

Thanks to the growing popularity of smartphones and other data-hungry
devices, the demand for mobile data is expected to grow 18-fold within the next
five years. To meet demand, wireless carriers are scrambling to boost network
capacity by installing more wireless base stations and shelling out billions of
dollars for the rights to broadcast on additional frequencies.

In tests at Rice, Argos allowed a single base station to track and send
highly directional beams to more than a dozen users on the same frequency at the
same time. The upshot is that Argos could allow carriers to increase network
capacity without acquiring more spectrum.

"The technical term for this is multi-user beamforming," said Argos
project co-leader Lin Zhong, associate professor of electrical and computer
engineering and of computer science at Rice. "The key is to have many
antennas, because the more antennas you have, the more users you can
serve."

Zhong said the theory for multi-user beamforming has been around for quite
some time, but implementing technology has proven extremely difficult. Prior to
Argos, labs struggled to roll out prototype test beds with a handful of
antennas.

"There are all kinds of technical challenges related to synchronization,
computational requirements, scaling up and wireless standards," he said.
"People have really questioned whether this is practical, so it's
significant that we've been able to create a prototype that actually
demonstrates that this works."

Argos presents new techniques that allow the number of antennas on base
stations to grow to unprecedented scales. The Argos prototype, which was built
by Rice graduate student Clayton Shepard, uses an array of 64 antennas and
off-the-shelf hardware -- including several dozen open-access test devices
called WARP boards that were invented at Rice's Center for Multimedia
Communications. In tests, Argos was able to simultaneously beam signals to as
many as 15 users on the same frequency. For wireless carriers, that performance
would translate to more than a six-fold increase in network capacity. Zhong said
the base-station design can be scaled up to work with hundreds of antennas and
several dozen concurrent users, which would result in much higher capacity
gains.

"There's also a big payoff in energy savings," Shepard said.
"The amount of power you need for transmission goes down in proportion to
the number of antennas you have. So in Argos' case, we need only about
one-sixty-fourth as much energy to serve those 15 users as you would need with a
traditional antenna."

Zhong and Shepard said Argos is at least five years away from being available
on the commercial market. It would require new network hardware and a new
generation of smartphones and tablets. It might also require changes in wireless
standards. Those are big hurdles, but Zhong said the potential benefits of
multi-user beamforming technology make it a very likely next big step for the
wireless industry.

"The bandwidth crunch is here, and carriers need options," Zhong
said. "They're going to pay close attention to any new technologies that
may allow them to serve more customers with fewer resources."

All rights reserved. Reproduction of this website,in whole or in part, in any form or medium without express written permission from cellular-news is prohibited. Your use of this website is subject to legal terms - Site Map.